The H2D with 40w laser is sitting in the garage. Pacific Northwest here, so temps in the garage in my location are under 70-80f ( 21-27c) tops even in July.
Installed a 4” vent through the wall to the outside, fight next to the printer to keep the hose runs short. Most of it is fixed rigid bends and Y splits. I’ve installed a 6” AC Infinity S6 up near the exit to the outside through the wall to pull air up from the workbench below. My thinking is the 6” fan (using 4-6 reducers of course ) will let me run then fan a bit slower than a 4” fan to keep the airflow at a similar level.
Below the fan the air intake forks to three different 4” ways , each with a blast gate to block it off. The shortest and closest to the fan intake is the one I’m connecting the H2D up to.
To get an idea of the speed to run the S6 at, I got my anemometer out and measure the air speed at the input to the blast gate (without the printer attached ) as well as out of the printer’s rear vent with the Bambu 4” vent pipe collar attached ( but no hose ).
The S6 fan at setting 1/10 pulled 157 ft/min in at the blast gate input.
The H2D blew out 373 ft/min at its 10% setting.
Then at full:
The S6 fan at 10/10 pulled 2105 ft/min at the blast gate input.
The H2D blew 2046 ft/min at its 100% setting.
So the two line up somewhat well in my plumbing arrangement.
So my thinking : tap the PWM control of the H2D fan
, send it out through a galvanically separated optocoupler circuit to the S6 so that the S6 gets set to the same level as the H2D is driving its fan. To be verified with an oscilloscope to check the actual duty cycles etc first.
Question:
Has anyone else done such interfaces between their H2D and an inline fan? If so, I’m interested in lessons learned and best approaches to drive for a good solution to share here.
As an aside , for completeness sake , I then attached the flexible 4” hose that came with the Bambu to the H2D rear fan flange , and with the H2D fan running at 100%, took another measure at the end of that 3-4 foot long flex hose to see how much is lost in drag down that hose. The 100% exit speed at the end of that 4” hose dropped from the 2046 ft/min from the flange direct at the fan exit, down to 1318 ft/min. A good 35% drop.
So with that hose in place I can run the S6 fan less than the 10/10, probably more around 7/10 level to keep the airflow going.
